A buck regulator is a circuit that generates a power supply that is at a lower voltage than the higher voltage power source from which it is derived. It improves the efficiency of an overall system, by delivering the current needed by a system from a lower voltage supply than the power source voltage itself. The main components of a buck regulator are a switch, a switch control circuit, an inductor, a diode and a capacitor. The switch is connected to the higher voltage power source and the duty cycle of the switch determines the fraction of the original power supply voltage that will be supplied by the buck regulator.
FIG. 1 illustrates a prior art version of a typical buck regulator. The pre-drivers shown at 16, 18 and 20 in FIG. 1 are needed to drive the final switch at 26 due to the typically large size of the switching device. The switch at 26 couples and decouples a power supply (shown as a battery) 28 to an inductor L 30. The inductor 30 is coupled to a capacitor C1 32 and a load Z 34. This provides an output Vout 36 as shown. A diode 38 is used to conduct the charging current during the time the switch is initially turned off and completes the loop. While switch 26 is closed, energy is transferred from the power supply 28 to the inductor 30 and capacitor 32. When switch 26 is open, current stored in the inductor flows through the loop created by the inductor 30, diode 38 and the parallel structure of the capacitor 32 and load 34. If desired, load 34 may be depicted separately from the rest of the circuit.
One issue with this solution is that the pre-driver inverters 16, 18, and 20 consume and hence waste power due to the shoot-through current that passes through them to ground as they switch between ON and OFF states. The charge on the gate-capacitance of the switch, 26, also wastes power as it is charged and discharged during every switching cycle. One goal of the present invention is to provide an alternative solution to increase efficiency by reducing the above wastage.